Rotary stepper switch



1967 w, M. OSTRANDER ETAL 3,358,251

' ROTARY STEPPER SWITCH Filed Feb. 17 1966 FIG. 1

2 Sheets-Sheet 1 I I N VENTORS t WALTER M. OSTRANDER F SINCLAIR NSUTHERLAND ATTORNEYS 1967 w. M. OSTRANDER ETAL 3,358,251

ROTARY STEFPER SWITCH Filed Feb. 17, 1966 2 Sheets-Sheet 2 4e 62 FIG 3INVENTORS WALTER M. OSTRAN Y SINCLAIR N SU HER D ATTORNEYS United Statesl atent Ofifice 3,358,251 ROTARY STEPPER SWETCH Walter M. Qstrander, NewMilford, and Sinclair N.

Sutherland, New Haven, Conn, assignors to Consolidated Electronicsindustries Corp., Waterbury, Conn,

a corporation of Delaware Filed Feb. 17, 1966, Ser. No. 528,300 Claims.(Cl. 335-122) The present invention relates to rotary electricalswitches, and more particularly to improvements in miniaturized, torsionspring driven, solenoid operated, stepper switches of the type adaptedto be used in sonar buoys and other like devices where unusually highdeceleration forces and shock are encountered in their intendedapplications.

Specifically, the miniaturized switch of the present inventionrepresents certain improvements over the stepper switch disclosed andclaimed in the copending application of Walter M. Ostrander, Arthur W.Bennett, and Sinclair N. Sutherland for Rotary Stepper Switch, Ser. No.306,185, filed Sept. 3, 1963, and now US. Patent No. 3,236,970.

The new switch, while performing the functions of the patented switch,is of a more simplified and improved construction, which lends itself tofaster and more economical production and provides more reliable andimproved performance. More specifically, the rotary stepper switch ofthe present invention includes a rotor which is rotated periodically bya clock spring under the control of an escapement mechanism to effect,in cooperation with a plurality of contacts, a predetermined switchingsequence. The escapement is of the novel type disclosed in the PatentNo. 3,236,970, and it unlocks the rotor for rotation when the rotorshaft is alternately axially displaced by a solenoid or spring force.

In accordance with the present invention, the rotor of the stepperswitch includes a predetermined array of shorting elements,advantageously in planar or so-called printed circuit form. Moreover andas an important aspect of the invention, the rotor is biased in an axialdirection by spring-loaded contact elements in order that they may beconstantly wiped by the rotor as it is rotated. Furthermore, the biasprovided by the springs associated with the cont-act elements serves tounlock the escapement when the solenoid is de-energized. As a stillfurther aspect of the invention, the springs which provide the requisitebiasing forces for each of the contact elements also serve as conductorsto connect the contact elements directly to the circuitry in which thesequential switching operations are being performed. It will beunderstood that the disposition of the contact elements and theconfiguration of the shorting elements may be appropriately arranged toprovide any desired switching sequence.

As will be appreciated, the new and improved arrangement enables rotarystepper switches of the type described to be assembled more easily andwith less exacting tolerances than have been heretofore necessary.Moreover, other simplifications to be described in detail hereinafterhave been incorporated in the switch construction to reduce costs, tosimplify the manufacture of parts and their subsequent assembly into afinished product, and to improve the reliability and accuracy of thesequential switching provided by the stepper switch.

For a more complete understanding of the present invention and itsattendant advantages, reference should be made to the following detaileddescription of its construction and operation taken in conjunction withthe accompanying drawings, in which:

FIG. 1 is an enlarged bottom plan View of the rotary Patented Dec. 12,1967 stepper switch of the present invention along with its associatedprinted circuitry;

FIG. 2 is a further enlarged, cross-sectional view of the switch of theinvention taken along line 2-2 of FIG 1;

FIG. 3 is a cross-sectional View of the switch taken along line 3-3 ofFIG. 2 and showing details of construction of the rotor and escapement;and

FIG. 4 is a fragmentary perspective view of the locking ring of theescapement.

Referring first to FIG. 2, the new and improved switch 10 includes asubstantially cylindrical housing 11 which is open at both ends and maybe advantageously fabricated in the form of an aluminum casting. Thebottom or lower end of the housing 11 is closed by a cap 12, while thetop or upper end of the housing is closed by a dielectric board 13 whichsupports a plurality of printed conductors 14- thereupon, whichconductors comprise part of an external pulsing circuit for a solenoidcoil 15.

Advantageously, pulsing circuitry for the solenoid 15, including circuitelements 16 (such as capacitors, resistors, silicon controlledrectifiers, etc.), may be arranged on and between the board 13 and asimilar board 17 which is spaced downwardly from the top of the housing,as shown in FIGS. 2 and 3. Both of the circuit boards 13, 17 may be madefrom a glass epoxy material and interconnecting posts 18 may be disposedtherebetween, which posts may extend from the boards as terminal posts.Also supported on the circuit board 13 are a plurality of printed outputconductors 19'.

More specifically and in accordance with the invention, a plurality ofspring-biased, switch contacts 21, 22, 23, 24, 25, 26 are supported in acircular block 27. Each of the contacts has enlarged annular headportions 21a- 2611 which are disposed for axial movement in cylindricalopenings 29 formed at the upper face of the block 27. As shown in FIG.2, the contacts have pointed shank portions 2117-2612 which projectdownwardly and through openings 30 formed at the lower face of the block27. In accordance with the invention, biasing springs 31, having theirupper free ends connected by solder 32 to the conductors 19, aredisposed in each of the openings 29 with their lower ends in downwardlybiasing contact with the heads Zita-26a of the contacts 21-26. As shown,the block 27 is fastened to printed circuit board 13 by one or morescrews 32.

In accordance with the inventive principles, the contacts 21-26 areselectively electrically connected by outer and inner printed shortingrings 36, 37, respectively, which are generally concentrically arrayedon a dielectric rotor disk 38 made of an epoxy glass material. The disk38 is supported through a bushing for rotation and axial displacement byshaft 39, which itself is supported for rotation and axial displacementby an inner housing member 41. The rings 36, 37 are electricallyindependent of one another but include radially inwardly projecting tabportions 36a, 37a, respectively.

More specifically, contact element 26 is disposed radiaL ly mostoutwardly of the axis of rotation of the rotor shaft 39 while contactelement 21 is disposed radially most inwardly of the axis. The remainingcontacts 22-25 are disposed at a radius intermediate those of thecontacts 21, 26 and along an arc which lies between (in acounterclockwise direction) the contacts 26, 21.

Thus as the rotor 39 is stepped (counterclockwise, for example) theouter shorting ring 36 will periodically and sequentially connect,through its tab portions 36a, the outermost contact element 26 with eachof the contact elements 22-25. Likewise, the inner shorting ring 37 willperiodically and sequentially connect, through its tab portion 37a, theinnermost contact element 21 with each of the contact elements 22-25.

As will be appreciated, by selectively arranging the angulardisplacements between individual ones of the contact elemnts, theangular displacements between the tab portions of the shorting rings,and the radial locations of the contact elements, a variety of switchingsequences may be established. Thus, as the spring-biased contacts 21-26are wiped by the steppingly rotated printed rotor disk, a selectedswitching sequence between the contacts is performed, which switchingsequence may be externally derived at the printed conductors 19 byvirtue of the interconnecting conductive springs 31.

Stepping of the rotor shaft 39 and the rotor disk 38 attached theretothrough a hub 40 is effected under the control of an escapementmechanism of the type claimed in the above-identified application andthrough torsional motive power provided by a wound clock spring 60 whichis appropriately, fixedly connected between the cap 12 and the lower end61 of the shaft 39. The escapement includes an escape tooth 45 which isaffixed to the rotor shaft 39 through the hub 40 and which is lockedagainst radial advance in an upper plane by upper teeth 46 and in alower plane by lower teeth 47. The teeth 46, 47 are in the form of alock ring 55 which is supported in the inner housing 41 by a pin 56, asshown in FIG. 3.

As the escape tooth 45 is axially displaced from one plane to the other,it is freed for limited rotation until it engages the next successivelocking tooth in its path. Thus, the rate of rotation or stepping of therotor shaft 35 is determined by the rate at which the escape tooth 45 isunlocked by an axial displacement into one or the other planes of thelocking teeth 46, 47. To that end, a solenoid coil assembly 49 includingthe coil 15 is mounted in the inner housing 41. When periodicallyenergized through the above-described pulsing circuit to which it isconnected by leads the solenoid coil attracts an armature plate 52,which is loosely mounted adjacent a shoulder 53 formed in the shaft 39.As will be understood, the attraction of the armature plate 52 by thecoil causes it to displace the shaft 39 axially upward. In turn, thismoves the locking tooth 45 out of the lower plane of the teeth 47 andinto the upper plane of the teeth 46, thereby permitting an incrementalrotational advance of the shaft 39 under the influence of the clockspring 60. Upon deenergization of the solenoid coil, the escape tooth 45is returned by the spring-biased contacts 21-26 to the lower plane for afurther incremental advance.

As described in more detail in the copending application, the innerhousing may be keyed through a key 61 to the housing 11 by a keyway 62formed therein for limited axial displacement when subjected todeceleration forces P, such as may be experienced in sonar buoyapplications when the switch ltl is dropped into the sea from greataltitudes. A shock spring 65 acting between the top of the switchassembly (defined by the printed circuit board 13) and an annularshoulder 66 formed in the inner housing resists displacement of theinner housing against the deceleration forces. A limit upon the upwarddisplacement of the rotor shaft 39 is provided by a stop 67 staked orotherwise secured to the printed circuit board 13, as shown in FIG. 2.

Advantageously and as shown best in FIGS. 1 and 2, the cap 12 is securedto the outer housing 11 by a spring clip 70 which has diametricallyinwardly opposed locking prongs 71 which project through openings 72, 73formed in the outer housing and cap, respectively. As will beunderstood, the prongs of the clips may be spread apart while the clipis in a plane normal to that of the cap. After the cap is locked to thehousing, the clip may be pivoted into the plane of the cap as indicatedin FIG. 2. A protective plastic sleeve 7 4 covers the central, generallyU-shaped portions of the clip.

The operation of the stepper switch is relatively simple. Torsionalmotive power for the rotor shaft 39 is provided by first rotating thecap 12 to wind the clock spring 60. When the spring is wound, the cap isclipped to the housing by the spring clip 74, as shown in FIG. 1.

The escape tooth 45 and the rotor disk 38 will assume a position in theplane of the lower locking teeth 47 under the influence of the springbiased contacts 21-2d. As will be understood, in the absence of axialdisplacement the shaft 39 is restrained against rotation by thecooperation of the escape tooth 45 With the locking teeth. Thereafter,the application of an energizing pulse to the solenoid coil 15 willcause the shaft 39 to be axially upwardly displaced, thereby freeing theescape tooth 45 from the lower teeth 47. Upon being freed, the escapetooth and the shaft' 39 are rotated under the influence of the storedenergy in the clock spring until the escape tooth is blocked by an uppertooth 46. Upon de-energization of the coil, the escape tooth will bedisplaced axially downwardly by the spring loaded contacts, therebybeing freed to allow a further incremental advance of the shaft underthe influence of the clock spring 60 until the escape tooth is halted bya lower tooth 47.

As will be appreciated, the periodic pulsing of the solenoid coil willcause the rotor disk 38 to be rotatingly stepped in synchronism with thepulsing rate. It will be understood that, the circuit conditions orswitching sequence at each step are determined by the specificinterrelationship of the inner, outer and intermediate contacts with theprinted shorting rings, which interrelationship may be changed asdesired or found necessary to meet a variety of stepping switchingapplications.

The abovedescribed rotary stepping switch provides extremely reliableand efficient operation. Furthermore, the new and improved arrangementof parts results in substantial cost savings in the manufacture ofstepping switches of this general type.

It should be understood that the specific switch mechanism hereinillustrated and described is intended to be representative only, ascertain changes may be made therein without departing from the clearteachings of the disclosure. Accordingly, reference should be made tothe following appended claims in determining the full scope of theinvention.

We claim:

1. In a miniaturized rotary stepper switch of the type including a rotorshaft mounted in a housing for step-bystep rotation under the influenceof a rotary drive means and a reversibly axially displaceable escapementmeans, the improvement comprising (a) a substantially planar,

ried by said shaft;

(b) planar shorting means carried by said rotor shaft;

(0) a plurality of switch contacts disposed adjacent to said shortingmeans;

((1) means supporting said contacts for limited axial displacement insaid housing;

(e) biasing spring means urging said contacts in a predetermined axialdirection;

(f) said contacts engaging said rotor element and thereby urging saidrotor in said predetermined axial direction;

(g) electromagnetic means selectively energizable to displace axiallysaid rotor in a direction opposite to said predetermined direction andagainst the force of said biasing springs;

(h) whereby the periodic energization of said electromagnetic meanscauses alternate axial displacements of said rotor shaft of sufficientmagnitude to unlock the escapement means and thereby causes a subsequentstep-by-step advance of said shaft under the control of said escapementmeans to rotate said shorting means relative to said array of switchcontacts and to effect a predetermined sequential interconnectionthereof.

2. A stepper switch in accordance with claim 1, in

which disklike rotor element car- (a) said disklike rotor and shortingmeans are of printed circuit construction.

3. A stepper switch in accordance with claim 2, in

which (a) said contacts include substantially pointed ends adapted toengage said printed rotor in predetermined limited areas.

4. A stepper switch in accordance with claim 1, in

which (a) said shorting means include a generally circular portion andan integral tab portion extending radially therefrom;

(b) said contacts are arrayed at two radial distances from the axis ofrotation of said rotor, one radius terminating within said generallycircular portion of said shorting means and the other radius terminatingwithin said tab portion.

5. A stepper switch in accordance with claim 1, in

which (a) said rotary drive means comprises a torsion spring;

(b) a selectively rotatable cap is included in said hous- (c) saidtorsion spring is connected between said housing and said cap;

(d) a removable spring clip means fastens said cap to said housing.

6. A stepper switch in which (a) said means supporting said contacts isa dielectric block;

(b) said block is mounted on a printed circuit board which closes off anend of the housing; and

(c) said printed circuit board includes output circuitry.

7. A stepper switch in accordance with claim 6, in

which (a) said block defines a plurality of cylindrical openings inwhich said contacts are disposed for limited axial displacement;

accordance with claim 1, in

(b) said biasing spring means comprise individual coil 0 springsdisposed in each of said openings; (c) said coil springs connect saidcontacts to said output circuitry. 8. A stepper switch in accordancewith claim 3, in which (a) said shorting means include first and secondgenerally circular portions which are generally concentric and areelectrically independent;

(b) said first and second circular portions having first and secondintegral radially extending tab portions, respectively;

(c) said contacts are arrayed at three radial distances from the axis ofrotation of said rotor;

(d) a first radius terminating within said first circular portion, asecond radius terminating within said second circular portion, a thirdradius terminating within one of said tab portions;

(e) at least one of said first and second tab portions intersecting oneof said second and first circular portions, said intersecting portionsbeing electrically independent and being separated by an area greaterthan the area of said pointed ends of said contacts.

9. In a rotary stepper switch of the type including a rotor shaftmounted in a housing for step-by-step rotation under the influence of arotary drive means and a reversibly axially displaceable escapementmeans, the improvement comprising (a) a rotary contact element carriedby said rotor shaft;

(b) a plurality of spring biased contact elements acting on said rotarycontact element and being collectively operative to urge said rotaryelement and said shaft in a first axial direction; and

(c) selectively energizable means for moving said rotary contact elementand said shaft axially in opposition to the collective action of saidspring biased contact elements.

10. A rotary stepper switch according to claim 9, further characterizedby (a) all of said spring biased contact elements act in the samedirection as said rotary contact element.

BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner.

9. IN A ROTARY STEPPER SWITCH OF THE TYPE INCLUDING A ROTOR SHAFTMOUNTED IN A HOUSING FOR STEP-BY-STEP ROTATION UNDER THE INFLUENCE OF AROTARY DRIVE MEANS AND A REVERSIBLY AXIALLY DISPLACEABLE ESCAPEMENTMEANS, THE IMPROVEMENT COMPRISING (A) A ROTARY CONTACT ELEMENT CARRIEDBY SAID ROTOR SHAFT; (B) A PLURALITY OF SPRING BIASED CONTACT ELEMENTSACTING ON SAID ROTARY CONTACT ELEMENT AND BEING COLLECTIVELY OPERATIVETO URGE SAID ROTARY ELEMENT AND SAID SHAFT IN A FIRST AXIAL DIRECTION;AND (C) SELECTIVELY ENERGIZABLE MEANS FOR MOVING SAID ROTARY CONTACTELEMENT AND SAID SHAFT AXIALLY IN OPPOSITION TO THE COLLECTIVE ACTION OFSAID SPRING BIASED CONTACT ELEMENTS.